Superjunction devices are well known and normally employ greatly deepened spaced base regions or pedestals of one conductivity disposed in a drift region of the other conductivity. By balancing the charge of the deep bases to that of the drift layer so that they deplete one another when the device is in a blocking condition, it is possible to use a higher concentration for drift region, resulting in reduced on resistance during forward conduction of the device.
A major problem in superjunction devices is in the formation of the ultra-deep base region. Thus, a large number of epitaxial layers with respective base implants, mask layers, implants and diffusions are sequentially formed. The large number of process steps cause the devices to be very expensive. It would be desirable to provide a process with a reduced number of mask steps for the manufacture of a superjunction device.